This paper describes the systematic method of an electron gun optimization.
The properties and quality of high power electron beams formed by an electron
gun were evaluated by measuring the electron beam emittance as a very sensitive
figure-of-merit. Our objective was to decrease the electron beam emittance by
identifying the most significant factors which influence the electron beam
quality and selecting the most preferable set of these factor levels. For this
purpose we used the experimental design method based on Taguchi techniques for
quality engineering. This technique proved to be a useful tool in identifying
the significant factors, optimizing its levels and decreasing the electron beam
emittance. As a result of our experiments we have obtained an optimized
electron gun which produces an electron beam with an emittance by one order of
magnitude lower than the emittance of a currently used beam. It was proven that
the repeatability of electron beam characteristics after each cathode
replacement is quite satisfactory provided that the cathode is placed in its
optimum position.